Miscellaneous notes about virtual groups (vgr)

Interrupting virtual group setup

	* When strn is adding groups and articles to a virtual group,
you can press any key to stop adding groups/articles.  Strn will then
print a message and display the articles which have been added.

Unread+read mode when all the vgr articles were read previously.

	* When entering a vgr, if all the articles in the vgr have
been read before, then the virtual scan mode will turn on unread+read.
This is done so that you can visit a virtual group even if all the
articles have been read before.  Here's an example:
	Suppose you read article <1234@foo.bar.com> in rec.humor.
You enter virtual scan mode with the following file:
begin virtual
score min off
score max off
filter unread+read
display unread
#The following is the only good joke in rec.humor:
+<1234@foo.bar.com>
end virtual

...You have already read <1234@foo.bar.com>.  When you start to read
the vgr, strn will detect that there are no unread articles in the vgr.
Strn will then turn on unread+read mode so that you can view the vgr.

Scoring:
	* If the "score min" value is greater than the "score max"
value, all articles from the following newsgroups will be excluded.
For instance, if you wanted to read all of "soc.*" with a score
greater than 1, but you didn't want to read "soc.culture.*", you could
do the following:

score min 99
score max 0
#the following groups will be excluded
+soc.culture.*

#Now set the scoring criteria for the groups I want to read:
score min 1
score max off
#This will include all of soc.*, except newsgroups that have already
#been listed.  (The soc.culture.* newsgroups will be excluded.)
+soc.*

	...This method of excluding newsgroups is very fast.

	* When reading an article in a vgr, scoring information will
not be loaded unless it is needed.  Any command which requires a score
will load the scoring information first.

	* When strn selects articles to place in a vgr, if all the
articles in the chosen newsgroup are scored, then the scoring rules
will not be loaded.
